[vcf-midatlantic] Does anyone know the substitute germanium transistor for a B1182

[Jameel akari]

-- 
Jameel Akari 

> On Jan 17, 2024, at 2:26 PM, corey cohen <coreyvcf at gmail.com> wrote:
> 
> Thanks,
> 
> I’ll start seeing if the data sheets match in spec once I can find a good copy of the B1182 since it is not officially listed as a cross with NTE127 of MPS3731 in any of my quick good searches.

Yeah I didn’t have time this morning to search the other way or match specs. It is possible there’s only a “close enough” match.

> 
> I wonder if the note about don’t use the newer design is related to silicon vs germanium.  I think NTE is the only ones to still make germanium transistors.  

I think what Tektronix was saying there is that while they used it and probably had spares, it was simply obsolete and/or out of production by then. It made sense when the design was new, and as part of a non-critical raster CRT assembly it wouldn’t be surprising if they (or the subassembly supplier) just kept making them the same way once they had a good-enough design.

/jka


> 
> Cheers,
> Corey
> 
> corey cohen
> uǝɥoɔ ʎǝɹoɔ
> Sent from my iPhone
> 
>>> On Jan 17, 2024, at 11:18 AM, Jameel Akari via vcf-midatlantic <vcf-midatlantic at lists.vcfed.org> wrote:
>>> 
>> MPS3731, which might be NTE127.
>> 
>> “Show your work:”
>> 
>> Tektronix used the same part in their 4023 terminal: (1)
>> 
>> Q106 151-0483-00 TRANSISTOR:GERMANIUM,PNP 17954 B1182
>> 
>> The supplier code 17954 they have there is
>> MIRATEL, DIV. BALL BROS RESEARCH CORP.
>> … which isn’t real helpful, they didn’t make the part.
>> 
>> But the Tektronix part number appears in their “Common Design Parts” catalog (2)
>> https://w140.com/tekwiki/images/0/06/Semiconductors_Common_Design_Parts_Catalog_1982.pdf <https://w140.com/tekwiki/images/0/06/Semiconductors_Common_Design_Parts_Catalog_1982.pdf>
>> 
>> On page 9-14 they have a cross-reference that lists it as MPS3731.
>> 
>> Page 6-22 has at least some of its specs to help match up.  They say it’s a TO-3 case, which is similar but chonkier than a TO-66.
>> The other specs imply that you do have to be careful matching it up… it’s good for 6 amps, 320 volts, but has a middling gain of 25, so the rest of the circuit was designed around that.
>> 
>> That page says “do not use in new design!” so it was well obsolete by the time this catalog was printed in 1982.
>> 
>> 
>> (1) https://bitsavers.org/pdf/tektronix/402x/070-1617-00_4023_Computer_Display_Terminal_Service_Manual_May81.pdf <https://bitsavers.org/pdf/tektronix/402x/070-1617-00_4023_Computer_Display_Terminal_Service_Manual_May81.pdf>
>> 
>> 
>> —
>> Jameel Akari
>> 
>> 
>>> On Jan 17, 2024, at 10:02 AM, corey cohen via vcf-midatlantic <vcf-midatlantic at lists.vcfed.org> wrote:
>>> 
>>> It’s a different package and I think in a lot of cases you can’t swap out germanium for silicon in older circuits so I’d prefer to stay with germanium.
>>> 
>>> Cheers,
>>> Corey
>>> 
>>>>> On Jan 17, 2024, at 9:04 AM, Sentrytv via vcf-midatlantic <vcf-midatlantic at lists.vcfed.org> wrote:
>>>> 
>>>> 
>>>> From: Sentrytv <sentrytv at yahoo.com>
>>>> Subject: Re: [vcf-midatlantic] Does anyone know the substitute germanium transistor for a B1182
>>>> Date: January 17, 2024 at 9:04:36 AM EST
>>>> To: Corey Cohen <corey at vcfed.org>, vcf-midatlantic <vcf-midatlantic at lists.vcfed.org>
>>>> 
>>>> 
>>>> According to NTE Electronics, B1182 OR 2sb1182 crosses over to an NTE 2527 PNP silicon complementary. Hi current switch.
>>>> TO251 case
>>>> 
>>>> Sent from:
>>>> My extremely complicated, hand held electronic device.
>>>> 
>>>>> On Jan 17, 2024, at 8:46 AM, corey cohen via vcf-midatlantic <vcf-midatlantic at lists.vcfed.org> wrote:
>>>>> 
>>>>> Hi,
>>>>> 
>>>>> Working on my dead ADM3a video, I realized I may need some spare parts before I start working on it.   
>>>>> 
>>>>> I tried to find a cross-reference to B1182 transistor which is Q106 on the video board.
>>>>> 
>>>>> This is a Germanium transistor in what seems to be a TO-66 case.
>>>>> 
>>>>> Spent an hour Googling and can’t find a cross reference and no one seems to have them available in the correct Germanium.
>>>>> 
>>>>> Thanks,
>>>>> Cheers,
>>>>> Corey
>>>>> 
>>>>> 
>>>>> 
>>>> 
>>>> 
>>>> 
>>> 
>>